Safety disconnect switch

ABSTRACT

A safety override disconnect switch particularly adapted for emergency use in the main electrical power supply of heavy equipment. The switch features an operator controlled axially fixed rotor having cam means for axially driving an axially movable contact-carrying element to close the switch, and heavy biasing means for strongly biasing the contacts away from the circuit connectors. In a preferred embodiment a backup cam system becomes operational should the contact-carrying axially movable element remain stuck to circuit connectors during reverse rotation of the operator controlled rotor.

United States Patent 1 Ege [ June 12, 1973 SAFETY DISCONNECT SWITCH [75]Inventor:

[73] Assignee: Underwriters Safety Devices Co.,

Chicago, Ill.

[22] Filed: May 19, 1972 [21] Appl. No.: 255,093

Hans Ege, Des Plaines, ll].

52 vs. C! 200/4, 200/11 EA, 200/63,

200/153 LB [51] Int. Cl. H01h 19/58 [58] Field of Search 200/4, 67 PK,153 LB,

[56] References Cited UNITED STATES PATENTS 2,502,952 4/1950 Jacobi200/4 2,762,876 9/1956 Glogau et al 200/11 EA 2,498,614 2/1950 Tregoning200/4 610,402 9/1898 l-lundhausen 200/67 PK Primary ExaminerDavid Smith,Jr. Attorney-Joseph P. OHalloran [57 1 ABSTRACT A safety overridedisconnect switch particularly adapted for emergency use in the mainelectrical power supply of heavy equipment. The switch features anoperator controlled axially fixed rotor having cam means for axiallydriving an axially movable contact-carrying element to close the switch,and heavy biasing means for strongly biasing the contacts away from thecircuit connectors.

in a preferred embodiment a backup cam system becomes operational shouldthe contact-carrying axially movable element remain stuck to circuitconnectors during reverse rotation of the operator controlled rotor.

10 Claims, 8 Drawing Figures PATENTED JUN] 2191:

sum 1 or 3 I PATENIEB JUN I 2 I973 SHEH3N3 This invention relates to asafety override disconnect switch which is particularly adapted for usein the main electrical power supply of heavy equipment such as miningmachinery and vehicles and the like. These switches are designed forcarrying high amperage, for example 400 amps. A preferred embodimentalso provides a positive safety disconnecting action in the event theswitch contacts stick together, and normal operation of the switchfails, for any reason.

It has been reported that there have been numerous accidents, someresulting in human fatality, which have resulted from the failure ofdisconnect switches, such as foot switches and other on-off switchespresently existing for example, in mining equipment and the like.Because of the high amperage service in which these switches arenormally used, there is at least a tendency for abutting contacts tostick to each other, in which event, normal operation of some switcheswould fail. That is, the electrical contacts would remain adhering toeach other, thwarting the disconnection of the power.

It is an object of the present invention to provide a safety overridedisconnect switch which is particularly adapted for use as a mainelectrical power supply switch in a high amperage system for instantlyshutting down the system in an emergency.

It is another object of the present invention to provide a safetydisconnect. switch which is particularly adapted for use in highamperage service, and which provides reliable disconnect operation.

It is another object of the present invention to provide a main powersupply safety override disconnect switch which is adaptable for use inconjunction with explosion proof housings.

It is a further object of a preferred embodiment of the presentinvention to provide a positive disconnect backup operation, topositively disconnect the contacts, should the normal operation of theswitch fail, for any reason.

These objects, and other objects which will be apparent hereinafter, areachieved in accordance with the present invention which is describedhereinafter and with the aid of the accompanying drawings in which:

FIG. 1 is a side view of a preferred embodiment of the switch of thepresent invention in an enclosure which is shown in cross section;

FIG. 2 is an enlarged elevational crosssectional view of the switchportion with the switch in the open" position and taken along the line22 in FIG. 1;

FIG. 3 is an enlarged side view of the switch with the contacts in theclosed position;

FIG. 4 is an enlarged side view showing the relative position of theoperating elements in the event the electrical contact stick, duringnormal disconnect operation;

FIG. 5 is an enlarged side view illustrating the positive lifting actionwhich forces the contacts to separate;

FIG. 6 is a top cross-sectional view taken approximately along the line6-5 In FIG. 5;

FIG. 7 is a fragmentary cross-sectional view taken approximately alongthe line 7-7 in FIG. 5; and

FIG. 8 is an exploded perspective view showing the various elements ofthe switch of the presentinvention.

Referring to FIG. I a preferred safety switch of the present inventionis generally indicated by the numeral 10. Switch 10 is shown mounted ona face plate 12 of a housing 14. Housing 14 is preferably of theexplosionproof type, and many constructions of explosion-proof housingsare presently available commercially. Consequently the details of theexpoIsion-proof construction features can be conventional and will notbe discussed further hereinafter, since they are not part of the presentinvention.

In order to simplify the further description of the switch of thepresent invention, various structural relationships will be describedusing directional terms such as above, below, etc., and these terms areintended to be applicable only when the switch is positioned so thatrotor element 22 is above axially movable element 28, and the axis ofrotation of rotor 22 is substantially verti cal as illustrated in thedrawings in FIGS. 1-5 and 8. Thus, as used herein, the terms above andbelow, horizontal, upwardly sloped, and the like are not intended to berestrictive except in this context, and are not to be construed asimplying that the switch is operational only when in any particularposition. Quite to the contrary, the switch of the present invention isoperational in any position.

The switch 10 is operated by means of shaft 16 which is controlled byhandle 18.

The overall construction and operation of the switch 10 can besummarized by reference to FIG. 8 which shows only the structuralelements actually associated with switch 10. In the following discussionlarger and more basic structural elements and relationships will bediscussed in sequences progressing from the top of F IG.

8 toward the bottom of FIG. 8, and thereafter the details of therespective elements and relationships will be discussed in sequenceprogressing from the bottom of FIG. 8, towards the top of FIG. 8. FIGS.3, 4, 5 and 6 are provided to illustrate the operation of a preferredembodiment. Referring to FIG. 8, control shaft 16 passes through opening18 in top plate 20 and a flange 21 at the inner end of shaft 16, issecured to a camcarrying rotor element 22. Flange segment 23 serves as arotation stop to limit the extent of rotation of rotor 22. A centered,elongated collar 24 which is secured to and extends downwardly fromrotor 22, mates over centered post 26 on axially movablecontact-carrying and cam follower carrying driven member 28. The arrow,a, shown in FIG. 8 adjacent rotor 22 indicates that the operationalmovement of element 22 during switching pivotally about the centralaxis, and the arrow, 12, adjacent contact-carrying element 28 indicatesthat element moves in an axial direction during switching.

Member 28 is biased axially towards top plate 20 by heavy coil springs30, 31 which reside in part inside respective collars 32, 33 which, inturn, reside in part in respective recesses 34, 35 in base elementgenerally indicated by the numeral 38. Base element 38 carries a pair offixed connectors 40, 41 on a power source side of the switch 10, andanother pair of fixed connectors 43, 44, respectively, on an equipmentside of switch 10. Contact bars 46, 48 are carried by axially movableelement 28 and operate to connect and disconnect the power supplycircuit. Contact bar 46 is sized to bridge between and butt againstrespective portions of connectors 40, 43 and second contact 48 is sizedto bridge between and butt against respective portions of connectors 41,44.

In the assembled condition, illustrated in FIGS. 1-7 herein, axiallymovable element 28 resides between posts 50, 51, 52, 53 which extendaxially upwardly, from base element 38 as seen in FIGS. 1 and 8. Just asconnectors 40, 41 reside between posts 50, 51, and connectors 43, 44reside between posts 52, 53, respectively, contact bars 46, 48 extendbetween these posts also, and this helps prevent substantial rotation ofmember 28 about the central axis indicated by the broken line 55 in FIG.8. Also, as indicated above, sleeves, or cups 32, 33 reside at leastpartially within and are axially movable within circular recesses 34, 35and this relationship also aids in preventing substantial rotation ofaxially movable member 28 around the central axis 55. However, it is tobe understood that due to normal manufacturing tolerances, someclearance between these structural elements is necessary, and at least asmall amount of pivoting of element 28 around the central axis ispossible and, indeed is encountered within the limits of theseclearances as a result of any angular forces exerted on axially movableelement 28. The greatest apparent movement of element 28 which isnormally encountered in the operation of this switch is its axialmovement and as indicated above this element is biased away fromconnectors 40, 41, 43, 44 by primary heavy springs 30, 31.

Bridging contact bars 46, 48 are also biased away from the centralsupport portion 59 of axially movable element 28 by secondary springs60, 61, 62, 63 which are shown in FIG. 7. Thus bars 46, 48 are fixedwith respect to element 28 in regard to movement of these elements aboutaxis 55, but are movable within small limits with respect to element 28in regard to axial movement, as indicated by the small arrows, c, inFIG. 8.

Referring to FIG. 2, support portion 59 of axially movable element 28 inspaced apart from bridging contacts 46, 48 because of the fact that thesecondary springs 60, 61, 62, 63 bias these elements apart. Duringmovement of element 28 to the closed contact position illustrated inFIG. 3, contact elements 46, 48 come to bear against connectors 40, 43,and 41, 44, respectively, and continued axially downward movement ofaxially movable member 28 causes further compression of the secondarysprings 60, 61, 62, 63 as indicated in FIG. 3 thus assuring continuousand very firm biasing of the bridge contacts 46, 48 against therespective connectors. Each contact 46, 48 is secured to support portion59 of axially movable member 28 by means of threaded studs 65 and nuts67. The positioning of nuts 67 on studs 65 will determine the limit ofthe extent of axial movement which contacts 46, 48 can undergo withrespect to support portion 59. In FIG. 3, contact bar 46, is showntightly compressed against connectors 40 and 43, it is noted that asmall gap exists between the top of nuts 67 and the underface of contact46.

Another advantage of this structural relationship is the fact thataxially movable element 28 is already in motion away from base 38 whennuts 67 strike contacts 46-48. This striking of the contacts from below,and the inertia of moving element 28 helps to dislodge contacts 46-48from contact with their respective connectors in normal operation.

Thus each pair of studs 65 and nuts 67 which is associated with therespective contact bars 46, 48 permit limited axial movement of bars 46,48, respectively, but prevent rotation of these bars with respect tosupport portion 59 of axially movable element 28.

The upper surface of axially movable member 28 includes a plurality ofelevated cam follower structures,

Y 4 70, 71, 72, 73 each of which includes an inclined surface portion 76and a horizontal surface portion 78.

Extending downwardly from rotor 22 are a plurality of cam structuresgenerally indicated by the numerals 80, 81, 82, 83, respectively, eachof which have an inclined portion 86 and a horizontally disposed bottomportion 88 (See FIG. 5). Cam structures 80, 83 are located on rotor 22to reside between respective cam follower structures -73, when theswitch is in the open position (See FIG. 1), and respective top portions76 of cam follower structures 70-73 and respective bottom portions 88 ofcam structures -83 are positioned so that these horizontal surfaceportions are axially aligned and butting when the switch is in thelocked closed configuration (See FIG. 3).

Structures 70-73 and 8083 are referred to herein as the primary camsystem, and this primary cam system operates, upon rotation of rotor 22about axis 55, to drive the axially movable cam follower element 28 inan axial direction, either away from rotor 22 to close the switch underthe driving force provided by rotation of handle 18, in which caseprimary springs 30, 31 are compressed, or upon rotation of handle 18 inan opposite direction, in which case the driving force causing axialmovement of element 28 towards rotor 22 is provided by springs 30, 31 innormal operation.

In a preferred embodiment of the present invention a second cam systemis utilized as a backup system to positively separate contact bars 46,48 from respective connectors in the event contact sticking occurs, andthe bias of springs 30, 31 is insufficient to cause separation.

Axially extending arms 90, 92 are directly secured to contact bars 46,48, respectively (See FIG. 2). Adjacent the axially upward extreme ofarms 90, 92 are cam follower pins 94, 96, respectively. Arms 90, 92 areof sufficient length and are so located as to extend upwardly throughrotor 22 and reside within arcuate slots 100, 102, respectively. Slots100, 102 include upwardly inclined cam surfaces 104, 106, respectively.Slots 100, 102 include upwardly inclined cam surfaces 104, 106,respectively which are located at that end of the slots 100, 102 whichare the trailing ends as rotor 22 rotates about axis 55 when rotor 22 isbeing rotated in the switch opening direction.

Arms 90, 92, pins 94, 96 and cam surfaces 105 provide what is referredto herein as a secondary cam system. Structural relationships andoperation of the secondary cam system are further illustrated with theaid of FIGS. 3-6.

FIG. 3 shows the switch in normal closed configuration, and it is notedthat the primary cam system is in the configuration in which respectivehorizontal surface 78, and 88 are butting. In the configuration shown inFIG. 3 the rotor 22 thus locks the axially movable element 28 in theswitch closed configuration preventing the contact bars 46, 48 frommoving axially away from the respective connectors. Moreover, in thisconfiguration, the secondary spring system comprising springs 60, 61,62, 63 continually urges the contact bars against respective connectorelements, against and overcoming the biasing action of the respectiveprimary springs 30, 31.

As the rotor element 22 is rotated in the direction indicated by arrow Din FIG. 4 inclined surface 76 of cam followers 70-73 would be normallyurged axially against inclined portion 86 of cam structures 80-83.

FIG. 4 is provided for the purpose of illustrating the relativeconfiguration in that unlikely, but dangerous circumstance in whichconductors 46, 48 stick to the respective connectors 40, 43, and 41, 44,respectively even though rotor 22 has been moved to the unlockconfiguration. Without the backup system referred to above, rotor 22would have no further control over the separation of the contacts 46, 48from their respective connectors. It is under these circumstances thatthe secondary cam surfaces 104 approach and engage cam follower pins 94,96 as illustrated in FIGS. 4, 5 and 6. As the rotation of cam rotor 22in the direction indicated by the arrow D in FIG. 4 leads to theconfiguration shown in FIG. 5 in which cam surfaces 105 bear againstpins 94 causing arm 90 to be urged axially, and lifting the contact bars96-98 as illustrated in FIG. 5. This action is further illustrated inFIG. 6 in which it is more clearly shown that secondary cam surfaces104106 are slotted to permit arms 90, 92 to rotate spring cam followerpins 94, 96 against secondary cam surfaces 104, 106. It is essentialthat means be provided to maintain rotor 28 in a fixed axial position,and in the illustrated embodiment (as shown in FIG. 1) this isaccomplished by securing rotor 22 close to plate 20 by securing handle18 to shaft 16 close to housing 12 where rotor 22 is so positioned. Thisassures cooperative alignment of pins 94, 96 and secondary cam surfaces104, 106, when axially movable element 28 is in stuck" position.

It is to be emphasized that the secondary cam system serves as a backupsafety system, and that normally the biasing of contacts 46, 48 awayfrom their respective connectors by springs 30, 31 is more than adequateto force separation and opening, to keep portions of the adjacent facesof the rotor 22 and cam-follower element 28 engaged. Biasing bysecondary springs 60, 61, 62, 63 must be strong enough to overpower thebias of springs 30, 31, when the switch is in closed position.

Another operational advantage flows from the particular switch structureof the present invention. This results in combined angular-axial vectorsfor separating stuck contacts. During normal closing of the switch,axially movable cam follower element 28 will initially be urged torotate about central axis 55 because of the pressure of cam surfaces 86against cam follower surfaces 76. As indicated above, very littlerotational movement of element 28 is permitted, but due to normalmanufacturing clearance tolerances, some definite amount of angularrotation of element 28 around axis 55 is in fact possible, and isencountered. Thus contacts 46, 48 will tend to be rotated, against theurging of springs 30, 31, in the clockwise direction, when viewed fromthe top, when rotor 22 is rotated in a clockwise direction. Whencontacts 46, 48 are initially seated against connectors 40, 43 and 41,44, respectively, the cam surfaces 86 and cam follower surfaces 76 willstill be engaged, and cooperating thus causing continued forcing of thecontacts 46, 48 against the respective conductors, along withcompression of secondary springs 60, 61, 62, 63 until the horizontalsurfaces 88, 78 slide across one another to the position shown in FIG.3. It is noted that the contacts 46, 48 will be at the extreme limit ofthe rotational movement permitted them in the clockwise direction whenseating or switch closing contact occurs. In normal switch openingoperation, contacts 46-48 will merely move axially from their seatedposition. In the event sticking occurs, however, and the rotor 22 isturned to the configuration shown in FIG. 4 so that secondary camsurfaces 104, 106 engage pins 94, 96, respectively, several vectors areapplied at ends 94, 96. One vector urges arms 90, 92 to rotate about thecentral axis, and this in turn causes contacts 46, 48 to be urged torotate about the central axis 55, as well. The second vector is theaxially directed vector which was referred to above causing straightline separation. It is our belief, based on observation, that thiscombined rotationally, and simultaneously axially directed urging of thecontacts 46, 48 accounts in part for the highly effective and reliablebackup separation which is provided by the secondary cam system inaccordance with the present invention.

Thus an important feature of one aspect of the present inventioninvolves the cooperation of cam elements on rotor 22 and axially movableelements 28 which constitutes means for positively and directly forcingthe bridging contact apart from the fixed conductors, particularly by acam system which applies both axial and rotational forces at theinterface between the contacts and connectors.

Having received this disclosure of the invention, and a particularlypreferred embodiment thereof, it will be apparent to those skilled inthe art that many modifications and variations thereof can be madewithout departing from the spirit or scope of the invention. Specificdisclosures and drawings are provided herein to illustrate a particularpreferred embodiment, and are not to be construed as limiting the scopeof the invention, which is defined in the claims appended hereto.

For example, rotor 22 and axially movable element support 28 could beused as shown in FIG. 8 with connectors 40, 41, 43, 44 being positionedabove contacts 46, 48 instead of below, and being supported by elementsdepending from top plate 20 instead of by bottom framing member 38. Insuch an embodiment the cams on the adjacent faces of rotor 22 andaxially movable support element 28, which are defined above as theprimary cam system, serve as the positive cam means for separatingcontacts 46, 48 from connectors 40, 43 and 41, 44, respectively, and asecondary backup cam system is unnecessary. In such an alternativeconfiguration the cams on the adjacent faces serve the same function asthe secondary cam system described and defined hereinbefore.

I claim:

1. A safety switch for opening and closing high amperage circuitscomprising a frame; a rotor; means for rotating said rotor through alimited are around its axis; means for securing said rotor againstsubstantial axial movement; an axially movable support element adjacentsaid rotor; said rotor and said support'element having mating alignmentmeans for maintaining the alignment of said support element with saidrotor, during the axial movement of said support element and rotation ofsaid rotor, said alignment means comprising an annular element which isconcentric with the axis of rotation of said rotor, and a mating elementextending axially and closely fitting said annular element, cooperatingcam means on adjacent faces of said rotor and said support element formoving said support element axially in a first direction in response torotation of said rotor in a first rotational direction through saidpredetermined 'arc; movable switch contact means for completing saidcircuit carried on said support element; circuit connector means fixedwith respect to said frame and positioned for contacting said contactmeans at the limit of the axial motion of the switch contact means insaid first axial direction, primary biasing means for biasing saidswitch contact means away from said connector means, and secondarybiasing means for biasing said contact means toward said connectormeans.

2. A safety switch for opening and closing high amperage electricalcircuits comprising a frame; a rotor; means for rotating said rotorthrough a limited arc around its axis; means for securing said rotoragainst substantial axial movement; an axially movable support elementadjacent said rotor said rotor and said support element having matingalignment means for maintaining the alignment of said support elementwith said rotor, during the axial movement of said support element androtation. of said rotor, said alignment means comprising an annularelement which is concentric with the axis of rotation of said rotor, anda mating element extending axially and closely fitting said annularelement; cam means on adjacent surfaces of said rotor and said supportelement for moving said support element axially in the direction awayfrom said rotor as said rotor is rotated through a predetermined areabout said axis in a first direction; movable switch contact means forcompleting said circuit carried on said support element; circuitconnector means fixed with respect to said frame and positioned forcontacting said contact means as said support element is moved axiallyin the direction away from said rotor; primary biasing means for biasingsaid contact means away from said connectors, and secondary biasingmeans for biasing said contact means away from said support element andtowards said connector means; said cam means including means forcompressing said secondary biasing means after said contact meanselectrically connects with said connectors; and locking means foraxially immobilizing said support element in the position in which saidsecondary biasing means is under compression, and said contact means iselectrically connected with said conductors; and means for moving theelectrically connected contact means away from said connectors when saidrotor is rotated through a predetermined arc in a direction oppositesaid first direction.

3. The switch of claim 2 which includes secondary cam means forpositively disengaging said contact means from said connector meanscomprising a first cam element fixed with respect to said contact, andextending axially in the direction toward said rotor, said first camelement including cam follower means, and in which said secondary camsystem includes cam surfaces on said rotor which are adapted to engagesaid cam follower means as the rotor is rotated about said axis in aswitch-opening direction.

4. A safety switch for opening and closing high amperage circuitscomprising: an insulating rectangular base element, said base elementhaving pairs of electrical connectors fixed at each side thereof, saidbase element including posts extending upwardly from each corner of saidbase element, said base element including a pair of recesses extendinginto said base element from the top thereof, each of said recesses beingaligned with respective pairs of said connecting elements; coil springbiasing means residing in said recesses; an axially movable switchcontact-carrying support element to which is secured a pair of cupsadapted to mate over said coil spring biasing means, and mate withinsaid recesses, said support element comprising a pair of contact meansfor bridging across and electrically connecting pairs of said respectiveconnector means, said contact means extending between and beingpositioned closely adjacent to said posts, whereby rotation of saidsupport elements around the rotors axis of rotation is substantiallyprevented; means for biasing said contact bars away from said supportelement; a rotor member, said support element and said rotor havingalignment means for maintaining these elements in operating alignmentwith respect to each other; said alignment means comprising an annularelement which is concentric with the axis of rotation of said rotor, anda mating element extending axially and closely fitting said annularelement; said rotor and said support element having at the adjacentfaces thereof cam means for driving said element in an axial directionaway from said rotor, as the rotor is moved through a predetermined arearound its central axis, handle means for rotating said rotor, platemeans adapted to be secured against the top of said posts maintainingcompression of the respective biasing spring means.

5. The switch of claim 4 includes axially extending secondary camfollower means carried by said support element and substantially fixedwith respect to said contact means, and secondary cam means on saidrotor for engaging said secondary cam follower means as said rotor isrotated about its axis in a switch opening direction, said secondary camfollower means being positioned to engage said secondary cam surfaces inthe event that said contacts stick to said connectors as said rotor isrotated in the switch opening direction to a position at which thecontact carrier element would normally begin to move axially away fromsaid connectors under the bias of said biasing means.

6. The switch of claim 4 wherein said secondary biasing means comprisesa pair of coil springs situated to bear against each of said contacts oneach side of each primary biasing means, and wherein said secondary cammeans includes a plurality of arm means which extend axially away fromsaid contact carrier element through slots in said rotor, and whereinsaid secondary cam follower means comprises cam follower membersextending from either side of said arm means radially, and whereinsecondary cam surface comprises an inclined plane situated at the wallsof said slots which are trailing said slots as the rotor is moved in theswitch opening direction, said inclined plane being sloped in thedirection in which said cam follower means is urged in the directionaway from said connectors.

7. A safety switch for opening and closing high amperage circuitscomprising a frame; a rotor; means for rotating said rotor through alimited are around its axis; means for securing said rotor againstsubstantial axial movement; an axially movable support element adjacentsaid rotor; said rotor and said support element having mating alignmentmeans for maintaining the alignment of said support element with saidrotor, during the axial movement of said support element and rotation ofsaid rotor, said aligment means comprising an annular element which isconcentric with the axis of rotation of said rotor, and a mating elementextending axially and closely fitting said annular element, cooperatingcam means on said rotor and said support element for moving said supportelement axially in a first direction in response to rotation of saidrotor through said predetermined arc; movable switch contact means forcompleting said circuit carried on said support element; circuitconnector means fixed with respect to said frame and positioned forcontacting said contact means at the limit of the motion of said switchcontact means in an axial direction opposite said first direction, andmeans for moving said contact means in said first direction to abuttsaid connector means.

8. A safety switch for opening and closing high amperage electricalcircuits comprising a frame; a rotor; means for rotating said rotorthrough a limited arc around its axis; means for securing said rotoragainst substantial axial movement; an axially movable support elementadjacent said rotor; cam means on adjacent surfaces of said rotor andsaid support element for moving said support element axially in thedirection away from said rotor as said rotor is rotated through apredetermined arc about said axis in a first-direction; movable switchcontact means for completing said circuit responsive to the movement ofsaid support element; circuit connector means fixed with respect to saidframe and positioned for contacting said contact means as said supportelement is moved axially in the direction away from said rotor; primarybiasing means for biasing said contact means away from said connectors,and secondary biasing means for biasing said contact means away fromsaid support element and towards said connector means; said cam meansincluding means for compressing said secondary biasing means after saidcontact means electrically connects with said connectors; and lockingmeans for axially immobilizing said support element in the position inwhich said secondary biasing means is under compression, and saidcontact means is electrically connected with said conductors; means formoving the electrically connected contact means away from saidconnectors when said rotor is rotated through a predetermined arc in adirection opposite said first direction; secondary cam means forpositively disengaging said contact means from said connector meanscomprising a first cam element fixed with respect to said contact, andextending axially in the direction toward said rotor, said first camelement including cam follower means, and in which said secondary camsystem includes cam surfaces on said rotor which are adapted to engagesaid cam follower means as the rotor is rotated about said axis in aswitchopening direction.

9. A safety switch for opening and closing high amperage circuitscomprising: an insulating rectangular base element, said base elementhaving pairs of electrical connectors fixed at each side thereof, saidbase element including posts extending upwardly from each corner of saidbase element, said base element including a pair of recesses extendinginto said base element from the top thereof, each of said recesses beingaligned with respective pairs of said connecting elements; coil springbiasing means residing in said recesses; an axially movable switchcontact carrying support element to which is secured a pair of cupsadapted to mate over said coil spring biasing means, and mate withinsaid recesses, said support element comprising a pair of contact meansfor bridging across and electrically connecting pairs of said respectiveconnector means; means for biasing said contact bars away from saidsupport element; a rotor member, said support element and said rotorhaving means for maintaining these elements in operating alignment withrespect to each other, said rotor and said support element having at theadjacent faces thereof cam means for driving said element in an axialdirection away from said rotor, as the rotor is moved through apredetermined arc around its centralaxis, handle means for rotating saidrotor, plate means adapted to be secured against the top of said postsmaintaining compression of the respective biasing spring means; axiallyextending secondary cam follower means carried by said support elementand substantially fixed with respect to said contact means, and asecondary cam means on said rotor for engaging said secondary camfollower means as said rotor is rotated about its axis in a switchopening direction, said secondary cam follower means being positioned toengage said secondary cam surfaces in the event that said contacts stickto said connectors as said rotor is rotated in the switch openingdirection to a position at which the contact carrier element wouldnormally begin to move axially away from said connectors under the biasof said biasing means.

10. A safety switch for opening and closing high amperage circuitscomprising: an insulating rectangular base element, said base elementhaving pairs of electrical connectors fixed at each side thereof, saidbase element including posts extending upwardly from each corner of saidbase element, said base element including a pair of recesses extendinginto said base element from the top thereof, each of said recesses beingaligned with respective pairs of said connecting elements; coil springbiasing means residing in said recesses; an axially movable switchcontact-carrying support element to which is secured a pair of cupsadapted to mate over said coil spring biasing means, and mate withinsaid recesses, said support element comprising a pair of contact meansfor bridging across and electrically connecting pairs of said respectiveconnector means; means for biasing said contact bars away from saidsupport element; a rotor member, said support element and said rotorhaving means for maintaining these elements in operating alignment withrespect to each other, said rotor and said support element having at theadjacent faces thereof cam means for driving said element in an axialdirection away from said rotor, as the rotor is moved through apredetermined arc around its central axis, handle means for rotatingsaid rotor, plate means adapted to be secured against the top of saidposts maintaining compression of the respective biasing spring means;secondary biasing means comprises a pair of coil springs situated tobear against each of said contacts on each side of each primary biasingmeans, and wherein said secondary cam means includes a plurality of armmeans which extend axially away from said contact carrier elementthrough slots in said rotor, and wherein said secondary cam followermeans comprises cam follower members extending from either side of saidarm means radially, and wherein secondary cam surface comprises aninclined plane situated at the walls of said slots which are trialingsaid slots as the rotor is moved in the switch opening direction, saidinclined plane being sloped in the direction in which said cam followermeans is urged in the direction away from said connectors.

I t k k tNnED STATES PATENT OFFICE QERTWICATE OF CGRRECTION P en2.729.109 Dated June 12, 1973 Inventor(s) Hans Ege It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column 1, line 61, *6-5 in" should read as 6-6-in-- Column 8, Claim 5,first line, after "H" insert --which-- Column 10, line 59, the word"trialing" should be changed to --trailing-- Signed and sealed this 12th(3 ay of March 19711..

(SEAL) Attest:

EDWARD M.FLETCHE R,JR. C. MARSHALL DANN Attesting Officer Commissionerof Patents FORM (10-69) USCOMM-DC 60376-P69 v1 v.5 GOVERNMENT PRINTINGOFFICE: 1909 o-aes-su UNHED STATES PATENT emits QERTEFIQATE 0F(IGRRECTEON Patent No. RJ'QQ ILOQ Dated June 12, 1973 Inventor(s) HansEge It is certified that error appears in the above-identified patentand that said Letters Patent are hereby corrected as shown below:

Column 1, line 61, "6-6 In" should read as "6-6 in-- Column 8, Claim 5,first line, after t" insert --which-- Column 10, line 59, the word"trialing" should be changed to -=--tra.iling-= Signed and sealed this12th day of March 197A.

( SEAL) Attest:

EDWARD M. FLETCHER, J R C. MARSHALL DANN Attesting Officer Commissionerof Patents USCOMM-DC 60376-P W U.S. GOVERNMENT PRINTING OFFICE: I969 0366- FORM PO-105O (10-69)

1. A safety switch for opening and closing high amperage circuitscomprising a frame; a rotor; means for rotating said rotor through alimited arc around its axis; means for securing said rotor againstsubstantial axial movement; an axially movable support element adjacentsaid rotor; said rotor and said support element having mating alignmentmeans for maintaining the alignment of said support element with saidrotor, during the axial movement of said support element and rotation ofsaid rotor, said alignment means comprising an annular element which isconcentric with the axis of rotation of said rotor, and a mating elementextending axially and closely fitting said annular element, cooperatingcam means on adjacent faces of said rotor and said support element formoving said support element axially in a first direction in response torotation of said rotor in a first rotational direction through saidpredetermined arc; movable switch contact means for completing saidcircuit carried on said support element; circuit connector means fixedwith respect to said frame and positioned for contacting said contactmeans at the limit of the axial motion of the switch contact means insaid first axial direction, primary biasing means for biasing saidswitch contact means away from said connector means, and secondarybiasing means for biasing said contact means toward said connectormeans.
 2. A safety switch for opening and closing high amperageelectrical circuits comprising a frame; a rotor; means for rotating saidrotor through a limited arc around its axis; means for securing saidrotor against substantial axial movement; an axially movable supportelement adjacent said rotor said rotor and said support element havingmating alignment means for maintaining the alignment of said supportelement with said rotor, during the axial movement of said supportelement and rotation of said rotor, said alignment means comprising anannular element which is concentric with the axis of rotation of saidrotor, and a mating element extending axially and closely fitting saidannular element; cam means on adjacent surfaces of said rotor and saidsupport element for moving said support element axially in the directionaway from said rotor as said rotor is rotated through a predeterminedarc about said axis in a first direction; movable switch contact meansfor completing said circuit carried on said support element; circuitconnector means fixed with respect to said frame and positioned forcontacting said contact means as said support element is moved axiallyin the direction away from said rotor; primary biasing means for biasingsaid contact means away from said connectors, and secondary biasingmeans for biasing said contact means away from said support element andtowards said connector means; said cam means including means forcompressing said secondary biasinG means after said contact meanselectrically connects with said connectors; and locking means foraxially immobilizing said support element in the position in which saidsecondary biasing means is under compression, and said contact means iselectrically connected with said conductors; and means for moving theelectrically connected contact means away from said connectors when saidrotor is rotated through a predetermined arc in a direction oppositesaid first direction.
 3. The switch of claim 2 which includes secondarycam means for positively disengaging said contact means from saidconnector means comprising a first cam element fixed with respect tosaid contact, and extending axially in the direction toward said rotor,said first cam element including cam follower means, and in which saidsecondary cam system includes cam surfaces on said rotor which areadapted to engage said cam follower means as the rotor is rotated aboutsaid axis in a switch-opening direction.
 4. A safety switch for openingand closing high amperage circuits comprising: an insulating rectangularbase element, said base element having pairs of electrical connectorsfixed at each side thereof, said base element including posts extendingupwardly from each corner of said base element, said base elementincluding a pair of recesses extending into said base element from thetop thereof, each of said recesses being aligned with respective pairsof said connecting elements; coil spring biasing means residing in saidrecesses; an axially movable switch contact-carrying support element towhich is secured a pair of cups adapted to mate over said coil springbiasing means, and mate within said recesses, said support elementcomprising a pair of contact means for bridging across and electricallyconnecting pairs of said respective connector means, said contact meansextending between and being positioned closely adjacent to said posts,whereby rotation of said support elements around the rotors axis ofrotation is substantially prevented; means for biasing said contact barsaway from said support element; a rotor member, said support element andsaid rotor having alignment means for maintaining these elements inoperating alignment with respect to each other; said alignment meanscomprising an annular element which is concentric with the axis ofrotation of said rotor, and a mating element extending axially andclosely fitting said annular element; said rotor and said supportelement having at the adjacent faces thereof cam means for driving saidelement in an axial direction away from said rotor, as the rotor ismoved through a predetermined arc around its central axis, handle meansfor rotating said rotor, plate means adapted to be secured against thetop of said posts maintaining compression of the respective biasingspring means.
 5. The switch of claim 4 includes axially extendingsecondary cam follower means carried by said support element andsubstantially fixed with respect to said contact means, and secondarycam means on said rotor for engaging said secondary cam follower meansas said rotor is rotated about its axis in a switch opening direction,said secondary cam follower means being positioned to engage saidsecondary cam surfaces in the event that said contacts stick to saidconnectors as said rotor is rotated in the switch opening direction to aposition at which the contact carrier element would normally begin tomove axially away from said connectors under the bias of said biasingmeans.
 6. The switch of claim 4 wherein said secondary biasing meanscomprises a pair of coil springs situated to bear against each of saidcontacts on each side of each primary biasing means, and wherein saidsecondary cam means includes a plurality of arm means which extendaxially away from said contact carrier element through slots in saidrotor, and wherein said secondary cam follower means comprises camfollower members extending from either side of said arm means radially,and wherein secondary caM surface comprises an inclined plane situatedat the walls of said slots which are trailing said slots as the rotor ismoved in the switch opening direction, said inclined plane being slopedin the direction in which said cam follower means is urged in thedirection away from said connectors.
 7. A safety switch for opening andclosing high amperage circuits comprising a frame; a rotor; means forrotating said rotor through a limited arc around its axis; means forsecuring said rotor against substantial axial movement; an axiallymovable support element adjacent said rotor; said rotor and said supportelement having mating alignment means for maintaining the alignment ofsaid support element with said rotor, during the axial movement of saidsupport element and rotation of said rotor, said aligment meanscomprising an annular element which is concentric with the axis ofrotation of said rotor, and a mating element extending axially andclosely fitting said annular element, cooperating cam means on saidrotor and said support element for moving said support element axiallyin a first direction in response to rotation of said rotor through saidpredetermined arc; movable switch contact means for completing saidcircuit carried on said support element; circuit connector means fixedwith respect to said frame and positioned for contacting said contactmeans at the limit of the motion of said switch contact means in anaxial direction opposite said first direction, and means for moving saidcontact means in said first direction to abutt said connector means. 8.A safety switch for opening and closing high amperage electricalcircuits comprising a frame; a rotor; means for rotating said rotorthrough a limited arc around its axis; means for securing said rotoragainst substantial axial movement; an axially movable support elementadjacent said rotor; cam means on adjacent surfaces of said rotor andsaid support element for moving said support element axially in thedirection away from said rotor as said rotor is rotated through apredetermined arc about said axis in a first direction; movable switchcontact means for completing said circuit responsive to the movement ofsaid support element; circuit connector means fixed with respect to saidframe and positioned for contacting said contact means as said supportelement is moved axially in the direction away from said rotor; primarybiasing means for biasing said contact means away from said connectors,and secondary biasing means for biasing said contact means away fromsaid support element and towards said connector means; said cam meansincluding means for compressing said secondary biasing means after saidcontact means electrically connects with said connectors; and lockingmeans for axially immobilizing said support element in the position inwhich said secondary biasing means is under compression, and saidcontact means is electrically connected with said conductors; means formoving the electrically connected contact means away from saidconnectors when said rotor is rotated through a predetermined arc in adirection opposite said first direction; secondary cam means forpositively disengaging said contact means from said connector meanscomprising a first cam element fixed with respect to said contact, andextending axially in the direction toward said rotor, said first camelement including cam follower means, and in which said secondary camsystem includes cam surfaces on said rotor which are adapted to engagesaid cam follower means as the rotor is rotated about said axis in aswitch-opening direction.
 9. A safety switch for opening and closinghigh amperage circuits comprising: an insulating rectangular baseelement, said base element having pairs of electrical connectors fixedat each side thereof, said base element including posts extendingupwardly from each corner of said base element, said base elementincluding a pair of recesses extending into said base element from thetop thereof, each of said recesseS being aligned with respective pairsof said connecting elements; coil spring biasing means residing in saidrecesses; an axially movable switch contact carrying support element towhich is secured a pair of cups adapted to mate over said coil springbiasing means, and mate within said recesses, said support elementcomprising a pair of contact means for bridging across and electricallyconnecting pairs of said respective connector means; means for biasingsaid contact bars away from said support element; a rotor member, saidsupport element and said rotor having means for maintaining theseelements in operating alignment with respect to each other, said rotorand said support element having at the adjacent faces thereof cam meansfor driving said element in an axial direction away from said rotor, asthe rotor is moved through a predetermined arc around its central axis,handle means for rotating said rotor, plate means adapted to be securedagainst the top of said posts maintaining compression of the respectivebiasing spring means; axially extending secondary cam follower meanscarried by said support element and substantially fixed with respect tosaid contact means, and a secondary cam means on said rotor for engagingsaid secondary cam follower means as said rotor is rotated about itsaxis in a switch opening direction, said secondary cam follower meansbeing positioned to engage said secondary cam surfaces in the event thatsaid contacts stick to said connectors as said rotor is rotated in theswitch opening direction to a position at which the contact carrierelement would normally begin to move axially away from said connectorsunder the bias of said biasing means.
 10. A safety switch for openingand closing high amperage circuits comprising: an insulating rectangularbase element, said base element having pairs of electrical connectorsfixed at each side thereof, said base element including posts extendingupwardly from each corner of said base element, said base elementincluding a pair of recesses extending into said base element from thetop thereof, each of said recesses being aligned with respective pairsof said connecting elements; coil spring biasing means residing in saidrecesses; an axially movable switch contact-carrying support element towhich is secured a pair of cups adapted to mate over said coil springbiasing means, and mate within said recesses, said support elementcomprising a pair of contact means for bridging across and electricallyconnecting pairs of said respective connector means; means for biasingsaid contact bars away from said support element; a rotor member, saidsupport element and said rotor having means for maintaining theseelements in operating alignment with respect to each other, said rotorand said support element having at the adjacent faces thereof cam meansfor driving said element in an axial direction away from said rotor, asthe rotor is moved through a predetermined arc around its central axis,handle means for rotating said rotor, plate means adapted to be securedagainst the top of said posts maintaining compression of the respectivebiasing spring means; secondary biasing means comprises a pair of coilsprings situated to bear against each of said contacts on each side ofeach primary biasing means, and wherein said secondary cam meansincludes a plurality of arm means which extend axially away from saidcontact carrier element through slots in said rotor, and wherein saidsecondary cam follower means comprises cam follower members extendingfrom either side of said arm means radially, and wherein secondary camsurface comprises an inclined plane situated at the walls of said slotswhich are trialing said slots as the rotor is moved in the switchopening direction, said inclined plane being sloped in the direction inwhich said cam follower means is urged in the direction away from saidconnectors.